[Linux-cluster] Post-Join Delay?

While I was reading the documentation I came across an awkward statement:

"The Post-Join Delay parameter is the number of seconds the fence daemon (fenced) waits before fencing a node after the node joins the fence domain. The Post-Join Delay default value is 3. A typical setting for Post-Join Delay is between 20 and 30 seconds, but can vary according to cluster and network performance."

I usually leave this in the default value, but the docs refer to something in between 20 and 30.

So, what are your usually settings for this parameters?What is your recommendation?